linux-kernel - Re: [PATCH 3/4] hwmon: Add support for Amphenol ChipCap 2

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Date:   Thu, 9 Nov 2023 10:35:40 +0100
From:   Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
To:     Javier Carrasco <javier.carrasco.cruz@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Conor Dooley <conor+dt@...nel.org>,
        Jean Delvare <jdelvare@...e.com>,
        Guenter Roeck <linux@...ck-us.net>,
        Jonathan Corbet <corbet@....net>,
        Liam Girdwood <lgirdwood@...il.com>,
        Mark Brown <broonie@...nel.org>
Cc:     Rob Herring <robh@...nel.org>, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-hwmon@...r.kernel.org,
        linux-doc@...r.kernel.org
Subject: Re: [PATCH 3/4] hwmon: Add support for Amphenol ChipCap 2

On 09/11/2023 09:59, Javier Carrasco wrote:
> 
> 
> On 09.11.23 09:40, Krzysztof Kozlowski wrote:
>> On 08/11/2023 17:35, Javier Carrasco wrote:
>>>>> +
>>>>> +	data->regulator = devm_regulator_get_optional(dev, "vdd");
>>>>> +	if (!IS_ERR(data->regulator)) {
>>>>> +		ret = cc2_retrive_alarm_config(data);
>>>>> +		if (ret)
>>>>> +			goto cleanup;
>>>>> +	} else {
>>>>> +		/* No access to EEPROM without regulator: no alarm control */
>>>>
>>>> Test your code with deferred probe. Are you sure you handle it
>>>> correctly? To me, it looks like you handle deferred probe the same as
>>>> any error.
>>>>
>>> The -EPROBE_DEFER is propagated to the probe function and it is the
>>> returned value. I clarified the error path in v2 so no error messages
>>
>> Really?
>>
>> I see:
>> if (!IS_ERR(data->regulator)) {
>> 	// so you do not go here
>> } else {
>> 	goto dev_register;
>> }
>> dev_register is not error path. So how do you return EPROBE_DEFER?
>>
>> Which line of code does it?
>>
> EPROBE_DEFER is returned if the command window was missed, which is

How "command window was missed" is related to the place I commented?

> checked in cc2_retrieve_alarm_config() (there is a typo I just corrected
> -> cc2_retrive_alarm_config() in the current version). It could then
> happen where you added a comment, but not because
> devm_regulator_get_optional() failed.
> 
> Are you expecting a probe deferring if devm_regulator_get_optional()
> fails as well? Like if the regulator is still not ready when the
> function is called.

We talk only about this place. Not others.


Best regards,
Krzysztof